Edard Albee's Lolita tries to adapt Nabokov's novel for the stage: the story of Humbert Humbert's passion for the nymphet Dolores 'Lolita' Haze, what he is willing to do to get her, their tempestuous relationship, and what happens when he loses her.
To present the material Albee adds another character: called 'A Certain Gentleman', he is a narrator of sorts who accompanies Humbert Humbert through the story, commenting, moving things along.
A Certain Gentleman introduces himself to the audience in a scene-setting prologue as an author of sorts -- the author, in fact, of what they are seeing now, acknowledging Humbert to be "a creation of my mind" (albeit one that has gotten a bit out of hand).
A Certain Gentleman, in other words, is Albee ... sort of, and Nabokov too (but he's also a character in the play, the creator of the character who isn't quite a puppet in his hands).
It's here, of course, that Albee has made his first and greatest mistake -- the fatal one, in fact.
He opts to emphasise artifice, to remind the audience they are watching a play and that Humbert Humbert is a mere invention.
(He never lets them forget it either, as A Certain Gentleman sticks to Humbert throughout the play, almost like a shadow -- quite literally the author who just can't let go.)
Nabokov's Lolita also begins with an introduction -- but one that insists on the veracity of the story (and that is offered by an authority, not some vague 'certain gentleman').
Albee's approach perhaps could be justified -- if he presented artifice as convincingly (or easily) as Nabokov.
But he doesn't.
(Albee himself seems to have doubts about A Certain Gentleman: "Ignore him; do your very best to ignore him. He is parenthetical", Humbert tells the audience -- but then Albee himself doesn't allow for that.)
The Lolita story unfolds familiarly, but in the shorter space Humbert's insinuating himself into to the Haze household and then his conquest of Lolita aren't nearly as effective.
The loss, the search, and even the resolution similarly pale beside the original (a comparison that is perhaps unfair but inevitable).
There are occasional exchanges that Albee manages well -- some clever dialogue, and a few exchanges that get at the heart of the matters -- but these don't appear consistently enough.
There's also an annoying tendency to try cleverness -- Albee can't match Nabokov's sense of language and very specific type of wordplay, but he still tries for imitation rather than playing to his own strengths.
Nabokov book-titles, for example, are dropped in conversation; apparently that's meant to pass for cleverness (and, given everything else in the play, it almost does).
There's also no escaping that Albee appears to find Humbert's obsession extremely distasteful.
Nabokov allowed Humbert to tell his own story, and as shocking as Humbert's desires are they seem authentic and convincing.
Nabokov wasn't approving, but at least understanding; Albee isn't.
The presentation of the play -- with a considerable amount addressed straight to the audience, and the odd middleman that is A Certain Gentleman -- isn't entirely bad.
Albee certainly has some sense of theatre, even if the pacing and presentation seems a bit uneven (but it's a hard tale to compress on the stage).

Albee's Lolita was a famous Broadway flop -- despite starring Donald Sutherland as Humbert and Ian Richardson as A Certain Gentleman (though Albee apparently had ... issues with Sutherland).
It's not often revived and, one imagines, can't be easily staged, the character of Lolita being almost impossible to cast adequately.
But audiences are far better advised to stick to the novel, in any case.